Such watches are known and marketed. They are, conventionally, dive watches comprising a rotating inner bezels. One can also find watches whose dial rotates in order to create an aesthetic or surprising effect, or watches fitted with a rotating polarizer inserted between the dial and the crystal.
Whatever the type of rotating element, it is actuated using a control member accessible from the exterior of the case. This type of control member is generally formed of a stem passing through the case radially, a crown secured to the outer end of the stem and a pinion secured to its inner end. An assembly of this type is illustrated in FIG. 1, which shows a partial cross-section of a watch comprising a mobile element.
The watch shown in FIG. 1 comprises, in a conventional manner, a case 10 formed of a middle part 12, a cap 14 and a back cover 16 together defining a housing 18 in which a movement 20 is mounted. A crystal 22 closes the case 10 in a water resistant manner. A dial 24 is mounted on movement 20. A circular recess 26 made in middle part 12 forms a shoulder 28 at the height of dial 24. A rotating bezel 30, inserted between dial 24 and crystal 22, is partially housed in circular recess 26, which axially positions and guides the latter in rotation. The bottom face of rotating bezel 30 includes a first flat circular portion 32a arranged opposite the periphery of dial 24 so as to conceal the same, and a second flat circular portion 32b abutting shoulder 28. It further comprises an intermediate circular portion 32c located between the first and second flat portions 32a and 32b and forming a contrate toothing 34.
A control member 36 actuates rotating bezel 30. For this purpose, a hole 38 passes radially through middle part 12. An intermediate tube 40 having a particularly well-finished inner surface state is screwed inside hole 38. A stem 42 of longitudinal axis AA is mounted inside tube 40 such that the ends thereof project outside and inside case 10. A crown 44 is secured to a first proximal end, whereas a pinion 46 is secured to a second distal end. The stem 42-crown 44-pinion 46 assembly forms the control member 36 of bezel 30. The latter is arranged in middle part 12 such that pinion 46 meshes with contrate toothing 34. The rotation of crown 44 actuated by the user, thus causes bezel 30 to rotate inside case 10.
Pinion 46 is secured to the distal end of stem 42 by screws and by bonding. This method of securing pinion 46 guarantees the axial and angular positioning of the latter relative to stem 42, which allows the transmission of the rotational movement of the control member 36 to bezel 30. However, it will be observed that such a method of securing by screws and bonding is so strong that it is practically definitive. During a maintenance service, it is almost impossible to dismantle control member 36 without breaking stem 42. A simple solution to this problem consists in using a stem 42 whose end, having a square cross-section, is engaged in a hole in pinion 46 that also has a square cross-section. Pinion 46 is thus locked angularly. Axial positioning can be achieved using a circlip arranged at the end of stem 42, in a groove located in immediate proximity to pinion 46, on the distal side. In order to do this, stem 42 must be slightly longer than in the case of securing by screws-bonding, which cannot be envisaged because of the lack of space between pinion 46 and movement 20.
The invention overcomes this difficulty by proposing the use of a securing part that is arranged, not on the movement side, as in the previously proposed solution, but on middle part 12 side. This securing part is anchored in stem 42 and pinion 46 in order to position pinion 46 axially.